Ventilation is a continuous, controlled process of updating the gas composition of the air contained in the lungs. Ventilation of the lungs is ensured by the introduction of atmospheric air rich in oxygen into them and the removal of gas containing excess carbon dioxide during exhalation.

Pulmonary ventilation is characterized by the minute volume of breathing. At rest, an adult inhales and exhales 500 ml of air at a frequency of 16-20 times per minute (minute 8-10 l), a newborn breathes more often - 60 times, a 5-year-old child - 25 times per minute. The volume of the respiratory tract (where gas exchange does not occur) is 140 ml, the so-called harmful air; thus, 360 ml enters the alveoli. Infrequent and deep breathing reduces the volume of harmful space, and it is much more effective.

Static volumes include quantities that are measured after completion of a breathing maneuver without limiting the speed (time) of its implementation.

Static indicators include four primary pulmonary volumes: - tidal volume (VT - VT);

Inspiratory reserve volume (IRV);

Expiratory reserve volume (ERV);

Residual volume (RO - RV).

And also containers:

Vital capacity of the lungs (VC - VC);

Inspiratory capacity (Evd - IC);

Functional residual capacity (FRC - FRC);

Total lung capacity (TLC).

Dynamic quantities characterize the volumetric speed of air flow. They are determined taking into account the time spent performing the breathing maneuver. Dynamic indicators include:

Forced expiratory volume in the first second (FEV 1 - FEV 1);

Forced vital capacity (FVC - FVC);

Peak volumetric (PEV) expiratory flow (PEV), etc.

Lung volumes and capacities healthy person determines a number of factors:

1) height, body weight, age, race, constitutional characteristics of a person;

2) elastic properties lung tissue and respiratory tract;

3) contractile characteristics of inspiratory and expiratory muscles.

To determine pulmonary volumes and capacities, the methods of spirometry, spirography, pneumotachometry and body plethysmography are used.

For comparability of measurement results of lung volumes and capacities, the data obtained must be correlated with standard conditions: body temperature 37 o C, atmospheric pressure 101 kPa (760 mm Hg), relative humidity 100%.

Tidal volume

Tidal volume (TV) is the volume of air inhaled and exhaled during normal breathing, equal to an average of 500 ml (with fluctuations from 300 to 900 ml).

Of this, about 150 ml is the volume of air in the functional dead space (FSD) in the larynx, trachea, and bronchi, which does not take part in gas exchange. The functional role of HFMP is that it mixes with the inhaled air, moisturizing and warming it.

Expiratory reserve volume

The expiratory reserve volume is the volume of air equal to 1500-2000 ml that a person can exhale if, after a normal exhalation, he exhales maximally.

Inspiratory reserve volume

The inspiratory reserve volume is the volume of air that a person can inhale if, after a normal inhalation, he takes a maximum breath. Equal to 1500 - 2000 ml.

Vital capacity of the lungs

Vital capacity of the lungs (VC) is the maximum amount of air exhaled after the deepest inhalation. Vital vital capacity is one of the main indicators of the condition of the device external respiration, widely used in medicine. Together with the residual volume, i.e. the volume of air remaining in the lungs after the deepest exhalation, vital capacity forms the total lung capacity (TLC).

Normally, vital capacity is about 3/4 of the total lung capacity and characterizes the maximum volume within which a person can change the depth of his breathing. During quiet breathing, a healthy adult uses a small part of vital capacity: inhales and exhales 300-500 ml of air (the so-called tidal volume). In this case, the inspiratory reserve volume, i.e. the amount of air that a person is able to additionally inhale after a quiet inhalation, and the reserve volume of exhalation, equal to the volume of additionally exhaled air after a quiet exhalation, averages approximately 1500 ml each. During physical activity, tidal volume increases due to the use of inhalation and exhalation reserves.

Vital capacity is an indicator of lung mobility and chest. Despite the name, it does not reflect breathing parameters in real (“life”) conditions, since even with the highest demands placed on the respiratory system by the body, the depth of breathing never reaches the maximum possible value.

From a practical point of view, it is inappropriate to establish a “single” standard for the vital capacity of the lungs, since this value depends on a number of factors, in particular on age, gender, body size and position, and the degree of fitness.

With age, the vital capacity of the lungs decreases (especially after 40 years). This is due to a decrease in the elasticity of the lungs and the mobility of the chest. Women have on average 25% less than men.

The relationship with height can be calculated using the following equation:

VC=2.5*height (m)

Vital capacity depends on the position of the body: in a vertical position it is slightly greater than in horizontal position.

This is explained by the fact that in vertical position the lungs contain less blood. In trained people (especially swimmers and rowers), it can be up to 8 liters, since athletes have highly developed auxiliary respiratory muscles (pectoralis major and minor).

Residual volume

Residual volume (VR) is the volume of air that remains in the lungs after maximum exhalation. Equal to 1000 - 1500 ml.

Total lung capacity

Total (maximum) lung capacity (TLC) is the sum of respiratory, reserve (inhalation and exhalation) and residual volumes and is 5000 - 6000 ml.

Tidal volume testing is needed to assess compensation respiratory failure by increasing the depth of breathing (inhalation and exhalation).

Vital capacity of the lungs. Systematic physical education and sports contribute to the development of respiratory muscles and expansion of the chest. Already 6-7 months after starting swimming or running, the vital capacity of young athletes’ lungs can increase by 500 cc. and more. A decrease in it is a sign of overwork.

The vital capacity of the lungs is measured with a special device - a spirometer. To do this, first close the hole in the inner cylinder of the spirometer with a stopper and disinfect its mouthpiece with alcohol. After taking a deep breath, exhale deeply through the mouthpiece. In this case, air should not pass past the mouthpiece or through the nose.

The measurement is repeated twice, and the highest result is recorded in the diary.

The vital capacity of the lungs in humans ranges from 2.5 to 5 liters, and in some athletes it reaches 5.5 liters or more. The vital capacity of the lungs depends on age, gender, physical development and other factors. A decrease of more than 300 cc may indicate overwork.

It is very important to learn to take full, deep breaths and avoid holding them. If at rest the respiratory rate is usually 16-18 per minute, then when physical activity, when the body needs more oxygen, this frequency can reach 40 or whiter. If you experience frequent shallow breathing or shortness of breath, you need to stop exercising, note this in your self-monitoring diary and consult a doctor.

Presents enough high requirements to human health. Constant stress, increased workload, electromagnetic radiation, noise and a huge number of other negative factors can significantly reduce the quality and the person. Medicine says that proper breathing is the first thing you should pay attention to when you feel tired, nervous disorders and other similar ailments. High level The development of medicine has made it possible to establish that regular breathing training is extremely necessary to maintain the body normally, but before starting such training, you should definitely familiarize yourself with the following information.

Lungs are organs air breathing all mammals, birds, most amphibians, reptiles, some fish and humans.

In humans, they are the respiratory organ embedded in the chest cavity and adjacent on both sides to the heart. Their total capacity is 5000 cm³.
The human lungs are a cone-shaped organ. The base faces the diaphragm, and the top appears in the neck above the collarbone. The lungs themselves are covered with a membrane called the pleura, and consist of particles that are separated by deep notches. In a healthy person right lung larger in volume, size and has 3 parts, and the left one has two. On average, the weight of this organ in an adult is from 374 to 1914 g, and the total lung capacity is on average 2680 ml.

The tissue of the described organs in children has, and in adults, gradually acquires a dark color due to particles of dust and coal deposited in the connective base of the lungs.

The human lungs are also equipped with autonomic and sensory nerves.

When you inhale, the pressure in the organ is lower than atmospheric pressure, and when you exhale, it is higher. This is what allows air to enter the lung.

The total amount of oxygen that can be held in the lungs during maximum inspiration is called the total lung capacity. It includes the reserve capacity of the organ during inhalation, exhalation, as well as residual and tidal volume.

This indicator represents the amount of air entering the lungs during a quiet breath. The respiratory capacity of the lungs is on average approximately 300-800 ml. The inspiratory reserve volume represents the air that can still be inhaled after a person inhales calmly.

When inhaling, the reserve capacity of the lungs averages 2-3 thousand ml. It is due to this that the tidal volume of the lungs increases during physical activity. And this indicator when exhaling, accordingly, is the amount of air that can be exhaled after a calm exhalation. When exhaling, the reserve capacity of the lungs averages from 1 to 1.5 thousand ml. The residual volume of air is the amount remaining after the greatest exhalation; it is equal to 1.2-1.5 thousand ml. on average it is 3.5-4.5 thousand ml for men, and 3-3.5 thousand ml for women.

Normal breathing in medicine is called eipnea, rapid breathing is tachypnea, and a decrease in frequency is bradypnea. Shortness of breath is dipnea, and cessation of breathing is apnea.

Exercising significantly increases lung capacity. On average, the reserves of the respiratory apparatus are quite significant and the main task of each person is to use and improve them in order to improve health.

Since most people breathe shallowly, not enough air gets into the lungs and little oxygen reaches the tissues and cells. For this reason, the body remains full of toxins, and nutrients are not fully absorbed.

You can prevent the development of cellulite by learning to make the most of your lung capacity. You should be in nature more often, breathe deeper, and play sports. As the experience of many people shows, with the start of training, the lungs gradually straighten, which allows the body to withstand increasingly greater stress and cleanses it. Best result you will achieve by combining sports with self-massage.

There are four primary pulmonary volumes and four pulmonary capacities. Each container includes at least two lung volumes (Fig. 4).

Rice. 4. Components of pulmonary volume (Pappenheimer, 1950).

The volume of gas inhaled or exhaled during each breathing cycle is called tidal volume (VT). During quiet breathing, it is about 500 ml in adults. Approximately 150 ml of this volume fills the conducting airways - from the nasal cavity and mouth to the respiratory bronchioles - and does not take part in gas exchange; this is the anatomical dead space (VD). This leaves 350 ml for alveolar ventilation (VA). They are mixed with the volume of air remaining in the lungs after a quiet exhalation (functional residual capacity - FRC), which varies from 1800 ml in small women to 3500 ml in large men. At a respiratory rate of 12 per minute, VA will be approximately 12X350 ml, or 4.2 l/min. Calculating alveolar ventilation in this way is an oversimplification that assumes that the inspired gas moves in a straight front, when in fact the movement is wedge-shaped. A straight front of airflow would mean that with Vt reduced to the value of Vd, the alveolar ventilation would be 0. Because this front is wedge-shaped, some alveolar ventilation, although very small, can occur even if VT is less than VD. Thus, the given method for calculating ventilation is inaccurate when VT is reduced to a significant extent.

When alveolar pressure (PA) becomes equal to atmospheric pressure, exhalation stops and air flow stops. At this point there is a balance between the elastic traction of the lung and the tendency of the chest to expand. By contracting the muscles involved in exhalation, mainly the abdominal muscles, an additional volume of air can be exhaled. This is the expiratory reserve volume (POexpiratory volume), which varies according to the tidal volume. The amount of gas remaining in the lungs after maximum exhalation is the residual volume (00), which usually approaches 1200 ml. The residual volume is less than 30% of the total lung capacity (TLC) - the amount of gas that is contained in the lungs at the end of maximum inspiration. Vital capacity (VC) is the largest volume of air that can be exhaled after a maximum inhalation. In young healthy individuals, vital capacity is about 80% of the total lung capacity. When maximum exhalation is made during the study of vital capacity, the efforts of the respiratory muscles continue the flow of air until the pressure in the lung tissue exceeds that in the lumen of the small airways, which then collapse, holding a residual volume that can never be exhaled during life. Inspiratory capacity (EI) is the maximum volume of air that can be inhaled after a quiet exhalation. It is about 75% vital capacity. Inspiratory reserve volume (IRV) is the maximum volume of air that can be inhaled after a quiet inspiration.

Methods for measuring lung volumes. Vital capacity and its subdivisions (ROvd., ROvyd. and VT) are measured directly by conventional spirometry. Residual volume or functional residual capacity can be measured by the degree of change in the concentration of a known volume of an inert gas (usually helium) when breathing into a given volume of spirometer. Volume constancy is maintained by adding O 2 at the same rate at which exhaled CO 2 is removed by the absorber. This method can also measure TLC, but it is usually calculated by summing FRC and EDU. or OO and ZHEL. By making successive measurements after maximum exhalation, at the end of normal exhalation and with full inspiration, the values ​​of OO, FRC and TEL are obtained, respectively. The following formulas apply:

where V is the volume of the spirometer, a is the initial helium concentration in percent, b is the helium concentration in percent at the end of equilibration, and the asterisk indicates the calculated values ​​(00, FFU or TEL).

These quantities can also be determined by the method open system using nitrogen clearance. Nitrogen is flushed out of the lungs when breathing oxygen, and the amount of nitrogen exhaled is calculated by analyzing the nitrogen content of the exhaled air using a nitrometer.

The formula is as follows:

where V is the volume of the spirometer, a is the initial concentration of nitrogen in the lungs, b is the final concentration of nitrogen in the spirometer - lungs system, the calculated value is indicated by an asterisk.

You can see that:
Evd.= OEL - FOE;
OO = FFU - ROvyd.;
TEL = OO + VEL = FRC + Evd.

Clinical significance options for lung volumes and capacities. Statistical lung volumes are essentially anatomical values ​​and cannot be used to assess function, whereas changes in lung volumes may be associated with pathology affecting function.

For a 0.01° change in temperature there is a 0.5% difference in tidal volumes and therefore lung volumes must be normalized to body temperature and BTPS.

The surgeon John Hutchinson in 1844 became convinced that the vital capacity is greater in summer than in winter, and therefore adjusted the volumes to the average room temperature, which at that time was 15°.

During quiet breathing, a person inhales and exhales about 500 ml of air. This volume of air is called tidal volume (TO)(Fig. 3).

Rice. 3. Lung volumes and capacities

After a calm inhalation, a person can still inhale a certain amount of air as much as possible - this is inspiratory reserve volume (IRV), it is equal to 2500-3000 ml.

After a calm exhalation, you can still exhale as much air as possible - this expiratory reserve volume (ER expiratory volume), it is equal to 1300-1500 ml.

The importance of DO in maintaining gas exchange at rest.

Whereas, the feasibility of the existence of reserve volumes mainly lies in ensuring the intensification of gas exchange under load. In addition, RO exhalation, which, unlike ROvd, is present in the lung even during quiet breathing, has another important function - maintaining gas exchange during exhalation.

The amount of air that a person can maximally exhale after taking the deepest breath is called vital capacity of the lungs (VC). It consists of the tidal volume, the inspiratory reserve volume and the expiratory reserve volume (VC = DO + ROvd + RO ext) and is equal to an average of 3500-4000 ml.

Vital capacity is an indicator of the mobility of the lungs and chest. The value of vital capacity depends on age, gender, size, body position, and degree of fitness, the presence of cardiopulmonary pathology. Vital capacity decreases with age. This is due to a decrease in the elasticity of the lungs and the mobility of the chest. Women have vital capacity 25% less than men. VC depends on height, since the size of the chest is proportional to the rest of the body size. In young people, vital capacity can be calculated based on the following equation: vital capacity = 2.5 x height (m). In a vertical position, vital capacity is slightly greater than in a horizontal position. This is due to the fact that in an upright position the lungs contain less blood. Vital vital capacity is significantly higher in trained people. It is especially great in swimmers and rowers, since these athletes have highly developed auxiliary muscles.

Vital capacity and tidal volume, its components, can be determined using spirometry or spirography.

After exhaling as deeply as possible, a certain amount of air remains in the lungs - this residual volume (RV), it is equal to 1300 ml. TOL is always present in the lung and cannot be removed naturally. The function of the OOL is to constantly maintain the lung in an expanded state, the lung should not collapse, and the alveoli should not collapse.

OO in a healthy person young man is 20-30% of TEL. In the elderly and old age Vital capacity decreases, and OO increases. due to decreased elasticity of the lungs and chest.

The volume of air that is in the lungs at the end of a quiet exhalation is called functional residual capacity (FRC), or alveolar air. It consists of expiratory reserve volume and residual volume. Accordingly, the feasibility of the existence of FFU consists of the values ​​(functions) of ROvyd and OOL. Means, physiological significance FRC is that due to the presence of this capacity in the alveolar air, fluctuations in the content of O 2 and CO 2 associated with different concentrations of these gases in the inhaled and exhaled air are leveled out.

The FRC value depends on a number of factors. On average, in young people it is 2.4 liters, and in older people - 3.4 liters. Women have approximately 25% less FRC than men.

Maximum amount air that can remain in the lungs after a deep breath is called total lung capacity (TLC), it is equal to the sum of the residual volume and vital capacity.

Study of lung volumes and capacities as the most important indicators functional state of the lungs is of great importance not only for the diagnosis of diseases, but also in connection with environmental monitoring of the area and assessment of the respiratory state of the population in environmentally unfavorable areas.

Air is found not only in the alveoli, but also in the airways - the nasal cavity, nasopharynx, trachea, bronchi and bronchioles. The air in the airways does not participate in gas exchange, therefore the lumen of the airways is called dead space. During a quiet inhalation of 500 ml, only 350 ml of inhaled atmospheric air enters the alveoli. The remaining 150 ml is retained in the anatomical dead space.

Although gas exchange does not occur in the airways, they are necessary for normal breathing, since they humidify, warm, and clean the inhaled air from dust and microorganisms. When the receptors in the nasopharynx, larynx and trachea are irritated by dust particles and accumulated mucus, a cough occurs, and when the receptors in the nasal cavity are irritated, sneezing occurs. Coughing and sneezing are protective breathing reflexes.

In addition, dead space, which was previously wrongly called harmful, performs another important function. When you exhale, air enters it from the alveoli with high content CO 2 and low O 2 . On the next inhalation, the air contained in the dead space will reduce the partial pressure of O 2 (pO 2) entering with atmospheric air. pO 2 then drops, reaching the values ​​necessary for further stage respiration - gas exchange in the lung.

Ventilation volumes.

Ventilation is determined by the volume of air inhaled or exhaled per unit of time. A quantitative characteristic of pulmonary ventilation is minute volume of respiration (MOV)- the volume of air passing through the lungs in one minute. To determine the MRR, it is enough to know the DO and respiratory rate (RR):

MOD = DO x BH.

At rest, the MOD is 6-9 liters. During physical activity, its value increases sharply and amounts to 25-30 liters.

Since gas exchange between air and blood occurs in the alveoli, it is not the general ventilation of the lungs that is important, but the ventilation of the alveoli . Alveolar ventilation is less than pulmonary ventilation by the amount of dead space. If you subtract the volume of dead space from the tidal volume, you get the volume of air contained in the alveoli, and if you multiply this value by the respiratory rate, you get the minute volume of alveolar ventilation or, as it is more often called, minute volume of pulmonary ventilation (MVV). Based on what has been said, let’s express MOFL with the formula

MOVL=DOxChD – OMPxChD, then

MOVL=BH (DO – WMD), where

WMD – volume of dead space.

If we substitute specific values ​​into the resulting formula, it becomes clear that the efficiency of alveolar ventilation is higher with infrequent but deep breathing than with frequent shallow breathing.

Composition of inhaled, exhaled and alveolar air.

Atmospheric air, which a person breathes, has a relatively constant composition. There is less oxygen and more carbon dioxide in the exhaled air, and even less oxygen and more carbon dioxide in the alveolar air (Table 1)

Table 1.

Inhaled air contains 20.93% oxygen and 0.03% carbon dioxide, exhaled air contains 16% oxygen, 4.5% carbon dioxide, and alveolar air contains 14% oxygen and 5.5% carbon dioxide. Exhaled air contains less carbon dioxide than alveolar air. This is due to the fact that when you exhale, dead space air, which contains a slightly lower carbon dioxide content, is mixed with the alveolar air, and its concentration decreases.

Lung volumes and capacities

During the process of pulmonary ventilation, the gas composition of the alveolar air is continuously updated. The amount of pulmonary ventilation is determined by the depth of breathing, or tidal volume, and the frequency of respiratory movements. During breathing movements, a person’s lungs are filled with inhaled air, the volume of which is part of the total volume of the lungs. To quantitatively describe pulmonary ventilation, total lung capacity was divided into several components or volumes. In this case, the pulmonary capacity is the sum of two or more volumes.

Lung volumes are divided into static and dynamic. Static pulmonary volumes are measured during completed respiratory movements without limiting their speed. Dynamic pulmonary volumes are measured during respiratory movements with a time limit for their implementation.

Lung volumes. The volume of air in the lungs and respiratory tract depends on the following indicators: 1) anthropometric individual characteristics of a person and respiratory system; 2) properties of lung tissue; 3) surface tension of the alveoli; 4) the force developed by the respiratory muscles.

Tidal volume (VT) is the volume of air that a person inhales and exhales during quiet breathing. In an adult, DO is approximately 500 ml. The value of DO depends on the measurement conditions (rest, load, body position). DO is calculated as the average value after measuring approximately six quiet breathing movements.

Inspiratory reserve volume (IRV) is the maximum volume of air that a subject can inhale after a quiet inhalation. The size of the ROVD is 1.5-1.8 liters.

Expiratory reserve volume (ERV) is the maximum volume of air that a person can additionally exhale from the level of quiet exhalation. The value of ROvyd is lower in a horizontal position than in a vertical position, and decreases with obesity. It is on average 1.0-1.4 liters.

Residual volume (VR) is the volume of air that remains in the lungs after maximum exhalation. The residual volume is 1.0-1.5 liters.

Lung capacity. Vital capacity of the lungs (VC) includes tidal volume, inspiratory reserve volume, and expiratory reserve volume. In middle-aged men, vital capacity varies between 3.5-5.0 liters and more. For women, lower values ​​are typical (3.0-4.0 l). Depending on the methodology for measuring vital capacity, inhalation vital capacity is distinguished when, after a complete exhalation, the maximum deep breath and vital capacity of exhalation, when after full breath maximum exhalation is performed.

Inspiratory capacity (EIC) is equal to the sum of tidal volume and inspiratory reserve volume. In humans, EUD averages 2.0-2.3 liters.

Functional residual capacity (FRC) is the volume of air in the lungs after a quiet exhalation. FRC is the sum of expiratory reserve volume and residual volume. The value of FRC is significantly influenced by the level of physical activity of a person and body position: FRC is smaller in a horizontal position of the body than in a sitting or standing position. FRC decreases in obesity due to a decrease in the overall compliance of the chest.

Total lung capacity (TLC) is the volume of air in the lungs at the end of a full inhalation. TEL is calculated in two ways: TEL - OO + VC or TEL - FRC + Evd.

Static lung volumes may decrease under pathological conditions that lead to limited lung expansion. These include neuromuscular diseases, diseases of the chest, abdomen, pleural lesions that increase the rigidity of the lung tissue, and diseases that cause a decrease in the number of functioning alveoli (atelectasis, resection, scar changes in the lungs).